Accompanying reduction in size and thickness of electronic devices, electronic components each having a surface mount package are being increasingly used in these electronic devices. Specific examples of such a package include a package in which a semiconductor chip is mounted on a board, such as a Chip On Board (COB) package. Such a package has a structure in which a semiconductor chip is bonded to a board. Therefore, due to a difference in coefficient of thermal expansion (CTE) between the semiconductor chip and the board, deformation such as warpage of a package sometimes occurs by a change in temperature. Further, in such a package, an increase in warpage increases power for peeling the semiconductor chip from the board so that bonding reliability between the semiconductor chip and the board is decreased.
Furthermore, electronic devices are further required of reduction in size and thickness. In order to satisfy such a requirement, reduction in size and thickness of electronic components have been attempted, and along with this attempt, reduction in thickness of a board constituting a package of an electronic component has been studied. Such a board having a reduced thickness is likely to generate the warpage, and thus suppressing the generation of the warpage has been further required.
Additionally, in order to make electronic devices multifunctional, it is necessary to increase a number of electronic components to be incorporated. For satisfying this requirement, a form of package known as a Package on Package (PoP) is employed in which a plurality of sub-packages are laminated and mounted on a board, followed by further integrating the sub-packages and the board into a single package. For example, this PoP is frequently employed in portable terminal devices such as a smartphone and a tablet computer. Since this PoP is a form in which a plurality of sub-packages are laminated, the bonding reliability between sub-packages, for example, has been important. In order to increase the bonding reliability, reduction of the warpage in each package used as a sub-package is required.
For the reasons described above, even when the board is used as a thin board in a package, a board material for producing a board whose warpage, for example, can be sufficiently suppressed has been developed. Examples of such a board material include a resin composition described in International Publication No. WO 2012/099134.
International Publication No. WO 2012/099134 discloses a resin composition containing a maleimide compound having at least two N-substituted maleimide groups per one molecular structure, and a silicone compound having at least one amino group per one molecular structure.